When we magnify an image, the image is getting “closer” to the viewer.This means multiple screen pixels will map to a single texel because we want to maintain the same distribution of colors in the magnified image. So a question arises, which color should a pixel map to? In class, we learned about a few methods, such as nearest sampling and bilinear interpolation, that help a pixel determine which texel to map to. Nearest sampling simply chooses the texel that is closest to the pixel, while bilinear interpolating interpolates the colors of the surrounding texels.
When we minify an image, the object is moving “farther” away from the viewer. This means many texels may map to a single pixel. Some ways to resolve these aliasing issues include prefiltering using mipmaps (essentially lower resolution images) or supersampling.